LXRandR is a very basic monitor config tool utilizing X RandR extension. It's a GUI frontend of the command line program xrandr. LXRandR can let you change the screen resolution on the fly. Besides, when you run lxrandr with external monitor connected, its GUI will change, and show you some quick options to get your projector working correctly. This tool doesn't aim to be a full xrandr frontend. It's utility for grandma, not for geeks. LXRandR only gives you some easy and quick options which are intuitive. It's very suitable for laptop users who frequently uses projectors or external monitor and just want to get their work done without reading a lot of "geek-centered" manuals or command line tutorials.
WWW: http://lxde.org/